With some manufacturing processes, for example casting, it can be difficult to control the process accurately enough to obtain a completely consistent result. Where the component being manufactured has an important loadbearing function in an end product, it is known to undertake visual assessments and measurements of the component to determine if it is fit for its intended purpose.
It is known to manufacture turbine blades for a gas turbine engine using a casting process. Known inspection methods employ ultrasonic techniques to measure a thickness of an outer wall of a cast blade. The measured wall thickness is compared against a pre-defined minimum thickness which is known to cope with an expected load on the blade in an expected operating environment. The component is sentenced as pass or fail based on whether this pre-defined minimum external wall thickness is present around the blade circumference. A component which is sentenced as a fail may be scrapped at significant cost to the manufacturer.